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camc314
44fd320324
## Summary
- Splits `TSModuleDeclaration` into two dedicated declaration nodes:
- `TSExternalModuleDeclaration` for string-literal modules and module augmentations.
- `TSNamespaceDeclaration` for identifier-based `module` and `namespace` declarations.
- Removes `TSModuleDeclaration`, `TSModuleDeclarationName`, `TSModuleDeclarationBody`, and `TSModuleDeclarationKind`.
- Makes invalid combinations of names, bodies, and declaration kinds unrepresentable.
- Ensures only namespace declarations introduce a normal binding.
- Updates all AST consumers, generators, traversal, formatting, code generation, semantic analysis, lint rules, transforms, and serialization.
- Keeps normal and eager-raw ESTree output compatible: both declarations remain `TSModuleDeclaration` nodes.
- Allows experimental lazy raw deserialization to expose the two new node types directly.
## Breaking Change
The Rust AST changes from:
```rust
pub enum Declaration<'a> {
VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 32,
FunctionDeclaration(Box<'a, Function<'a>>) = 33,
ClassDeclaration(Box<'a, Class<'a>>) = 34,
TSTypeAliasDeclaration(Box<'a, TSTypeAliasDeclaration<'a>>) = 35,
TSInterfaceDeclaration(Box<'a, TSInterfaceDeclaration<'a>>) = 36,
TSEnumDeclaration(Box<'a, TSEnumDeclaration<'a>>) = 37,
TSModuleDeclaration(Box<'a, TSModuleDeclaration<'a>>) = 38,
TSGlobalDeclaration(Box<'a, TSGlobalDeclaration<'a>>) = 39,
TSImportEqualsDeclaration(Box<'a, TSImportEqualsDeclaration<'a>>) = 40,
}
pub struct TSModuleDeclaration<'a> {
pub node_id: Cell<NodeId>,
pub span: Span,
pub id: TSModuleDeclarationName<'a>,
pub body: Option<TSModuleDeclarationBody<'a>>,
pub kind: TSModuleDeclarationKind,
pub declare: bool,
pub scope_id: Cell<Option<ScopeId>>,
}
```
to:
```rust
pub enum Declaration<'a> {
VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 32,
FunctionDeclaration(Box<'a, Function<'a>>) = 33,
ClassDeclaration(Box<'a, Class<'a>>) = 34,
TSTypeAliasDeclaration(Box<'a, TSTypeAliasDeclaration<'a>>) = 35,
TSInterfaceDeclaration(Box<'a, TSInterfaceDeclaration<'a>>) = 36,
TSEnumDeclaration(Box<'a, TSEnumDeclaration<'a>>) = 37,
TSExternalModuleDeclaration(Box<'a, TSExternalModuleDeclaration<'a>>) = 38,
TSNamespaceDeclaration(Box<'a, TSNamespaceDeclaration<'a>>) = 39,
TSGlobalDeclaration(Box<'a, TSGlobalDeclaration<'a>>) = 40,
TSImportEqualsDeclaration(Box<'a, TSImportEqualsDeclaration<'a>>) = 41,
}
pub struct TSExternalModuleDeclaration<'a> {
pub node_id: Cell<NodeId>,
pub span: Span,
pub id: StringLiteral<'a>,
pub body: Option<Box<'a, TSModuleBlock<'a>>>,
pub declare: bool,
pub scope_id: Cell<Option<ScopeId>>,
}
pub struct TSNamespaceDeclaration<'a> {
pub node_id: Cell<NodeId>,
pub span: Span,
pub id: BindingIdentifier<'a>,
pub body: TSNamespaceDeclarationBody<'a>,
pub kind: TSNamespaceDeclarationKind,
pub declare: bool,
pub scope_id: Cell<Option<ScopeId>>,
}
pub enum TSNamespaceDeclarationBody<'a> {
TSNamespaceDeclaration(Box<'a, TSNamespaceDeclaration<'a>>) = 0,
TSModuleBlock(Box<'a, TSModuleBlock<'a>>) = 1,
}
pub enum TSNamespaceDeclarationKind {
Module = 0,
Namespace = 1,
}
```
The corresponding inherited `Statement` variants, `AstKind` variants, builders, and visitor methods have also changed.
## Why?
`TSModuleDeclaration` previously represented two declaration families with different syntax and semantics:
```ts
declare module "foo" {}
declare module "*.css";
module Foo {}
namespace Foo {}
namespace Foo.Bar {}
```
The shared representation allowed invalid states such as:
- A namespace with a string-literal name.
- An external module with an identifier name.
- An identifier namespace without a body.
- A dotted external module.
- An external module containing another module declaration as its body.
- A declaration whose `kind` disagreed with its name.
Consumers also had to inspect `id` before determining whether the node introduced a binding or represented an external module.
The two declaration families have stronger independent invariants:
### External modules
- Always have a string-literal name.
- Never introduce a normal binding identifier.
- May omit their body.
- Cannot use dotted names.
- Use module-body import and export rules.
### Namespace declarations
- Always have a binding identifier.
- Always have a body.
- May contain nested namespace declarations for dotted names.
- Explicitly preserve the `module` or `namespace` spelling.
- Introduce a namespace/module symbol.
- Use namespace-body restrictions.
Dedicated nodes encode these differences directly.
## Declaration forms
External modules use `TSExternalModuleDeclaration`:
```ts
declare module "foo" {}
declare module "*.css";
module "foo" {}
```
Identifier-based declarations use `TSNamespaceDeclaration`:
```ts
module Foo {}
namespace Foo {}
```
Dotted namespaces are represented as nested namespace declarations:
```ts
namespace Foo.Bar {}
```
```rust
TSNamespaceDeclaration {
id: Foo,
body: TSNamespaceDeclarationBody::TSNamespaceDeclaration(
TSNamespaceDeclaration {
id: Bar,
body: TSNamespaceDeclarationBody::TSModuleBlock(...),
// ...
}
),
// ...
}
```
Only `TSExternalModuleDeclaration::body` is optional.
## ESTree compatibility
Normal serialization and eager raw deserialization continue to emit the existing ESTree shape:
```ts
interface TSModuleDeclaration {
type: "TSModuleDeclaration";
id: BindingIdentifier | StringLiteral | TSQualifiedName;
body: TSModuleBlock | null;
kind: "module" | "namespace";
declare: boolean;
global: false;
}
```
Dotted namespaces continue to serialize as a single `TSModuleDeclaration` with a `TSQualifiedName`.
Experimental lazy raw deserialization is not compatibility-preserving. It now exposes `TSExternalModuleDeclaration` and `TSNamespaceDeclaration` directly, with separate constructors, layouts, and visitor type IDs.
## How to migrate
Code that previously matched all forms through one variant:
```rust
if let Declaration::TSModuleDeclaration(declaration) = declaration {
// ...
}
```
should now match the required declaration family:
```rust
match declaration {
Declaration::TSExternalModuleDeclaration(declaration) => {
// String-literal external module
}
Declaration::TSNamespaceDeclaration(declaration) => {
// Identifier-based module or namespace
}
_ => {}
}
```
The same applies to `Statement` and `AstKind`:
```rust
Statement::TSExternalModuleDeclaration(declaration)
Statement::TSNamespaceDeclaration(declaration)
AstKind::TSExternalModuleDeclaration(declaration)
AstKind::TSNamespaceDeclaration(declaration)
```
Common field migrations:
| Previous representation | New representation |
| --- | --- |
| `TSModuleDeclarationName::StringLiteral(id)` | `TSExternalModuleDeclaration::id` |
| `TSModuleDeclarationName::Identifier(id)` | `TSNamespaceDeclaration::id` |
| `body: None` | Only valid on `TSExternalModuleDeclaration` |
| `TSModuleDeclarationBody::TSModuleBlock` | External `body` or `TSNamespaceDeclarationBody::TSModuleBlock` |
| `TSModuleDeclarationBody::TSModuleDeclaration` | `TSNamespaceDeclarationBody::TSNamespaceDeclaration` |
| `TSModuleDeclarationKind::Module` | External module, or `TSNamespaceDeclarationKind::Module` |
| `TSModuleDeclarationKind::Namespace` | `TSNamespaceDeclarationKind::Namespace` |
| Inspect `id` to determine binding behavior | Match `TSNamespaceDeclaration` |
| `declaration.id()` for string modules | Now returns `None` |
| `visit_ts_module_declaration` | `visit_ts_external_module_declaration` or `visit_ts_namespace_declaration` |
When constructing nodes, use the generated `TSExternalModuleDeclaration` or `TSNamespaceDeclaration` builders rather than recreating the previous shared representation.
fixes https://github.com/oxc-project/backlog/issues/218